Errata exists for this version of the document.

Network traffic and application layer Messages may be captured or modified and forwarded to OPC UA Clients, Servers, and Subscribers. Message alteration may allow illegitimate access to a system.

Message alteration impacts Integrity, Authorization, Auditability, Non-Repudiation and during session / secure channel establishment Authentication.

See 5.1.5 for the reconciliation of this threat.